Conor McGregor pictured in a pub in Ireland, posted on Facebook Sunday night at 11.36pm

In August, Conor McGregor was one half of one of the richest fights in boxing history. Three months on, there are concerns he may never fight again.

Having risen to the top of the UFC, the Irishman took on his ultimate challenge – a boxing clash with former five-weight world champion Floyd Mayweather.

The money-spinning Las Vegas showdown capped a remarkable rise for the MMA star, who was still collecting benefits in his native Dublin as late at 2013.

In a historic cross-over clash that smashed previous UK pay-per-view records, the Irishman defied many pre-fight predictions by taking the unbeaten Mayweather into the 10th round.

McGregor courted controversy earlier in November when he pushed a referee at Bellator 187

Dana White believes McGregor's behaviour is partly due to the fact that he's 'a god in Ireland'

The Irish UFC star fought Floyd Mayweather in a lucrative boxing showdown in August

He was eventually beaten on his professional debut as 'Money' stretched his perfect record to 50-0. But following a frenetic build-up fraught with expletives and excitement, McGregor appeared the obvious heir to his retiring conqueror's crown as the king of combat sports.

He had earned $75million (£55.7m), fought the finest fighter of his generation and cemented his place as one of the biggest superstars in world sport.

In the 95 days since stepping out into the lights of Las Vegas, however, the Irishman has gone from the crest of a wave to increasingly choppy waters – all without lacing up the gloves again.

He remains the UFC's lightweight champion and mouth-watering fights with Tony Ferguson and rival Nate Diaz are still in the pipeline.

But having hit the headlines for recent exploits both in and out of the Octagon, UFC chief Dana White fears the combat career of his most famous charge could be over.

'Conor might never fight again. The guy's got $100 million,' he said on Tuesday.

'I've got guys that made less than that and were lawyers and went to school their whole life and quit working.'

The explosive build-up to the fight suggested McGregor was the heir to Mayweather's throne

Now, UFC chief White has hinted McGregor's riches may mean he does not fight again

White said: 'Try to get up and get punched in the face every day when you've got $100million'

He added: 'Try to get up and get punched in the face every day when you've got $100million in the bank... Money changes everything with a lot of people.'

For all of McGregor's riches, however, his recent conduct hardly hints at a lack of motivation.

The UFC star was in a bar in Dublin's south side on Sunday night when the fight is alleged to have occurred.

As of Tuesday night, Irish police are still not investigating the incident, which saw two men punched in the face, as no criminal complaint has been made.

But a senior source told the Mail: 'No-one wants to see one of Ireland's most high-profile sports celebrities – and icon to kids all over Ireland – dragged into a bitter row involving serious criminals.

'There is a possibility that the cartel might now get involved to stop anyone escalating further. Conor McGregor is well liked and respected.'

Since fighting Mayweather, McGregor has gone from the crest of a wave to choppy waters

McGregor uploaded a public apology for his actions at Bellator on his Instagram account

McGregor has a flamboyant lifestyle but recent incidents have not reflected well on him

The 29-year-old has been linked with a third fight against bitter rival Nate Diaz (right)

Earlier this month, however, there was no ambiguity about McGregor's involvement in another unsavoury incident – this time inside the Octagon.

At Bellator 187 in Dublin on November 10, 'the Notorious' clambered into the Octagon to celebrate team-mate Charlie Ward's victory over John Redmond.

McGregor was only a spectator for the MMA event. But the fracas, which was captured on video, has had far-reaching implications for his own career inside the Octagon.

McGregor later apologised for his role in the incident, writing on Instagram: 'While trying to support a loyal team-mate and friend, I let my emotions get the best of me and acted out of line.

White believes that McGregor's life away from sport could lower his motivation to fight

Despite defeat by Mayweather, McGregor has also been linked with a return to boxing

'As a multiple weight UFC champion, executive producer, role model and public figure, I must hold myself to a higher standard.

Unfortunately, the Irishman's apology did not wash with the authorities. Association of Boxing Commissions (ABC) head Mike Mazzulli, who was in the arena that night, claimed that, as a punishment, McGregor would no longer fight at UFC 219 in Las Vegas next month.

McGregor's manager Audie Attar rubbished those reports. But White has now confirmed that the 29-year-old had been pulled from the card.

'He was being dealt with by the head of the ABC,' White said.

'We were gonna fight him, regardless of what Audie says. We were working on a fight for him at the end of the year. And he's just not ready.'

But what is behind McGregor's recent behaviour? For White, it's simple.

'He's a young, rich kid who is a god in Ireland,' he said. 'That's not the healthiest environment either. It's all part of it.

'When he travels, he's got people for days with him. When you make that kind of money, you're that famous and you're a professional athlete, you're gonna have an overload of cling-ons.'

His foe back in August is no stranger to having a big entourage. And despite defeat in his professional debut, there remains a chance McGregor could again swap the Octagon for the squared-circle.

McGregor has been called out by his former sparring partner, Paulie Malignaggi

The Irishman was called out by former sparring partner Paulie Malignaggi following the Mayweather fight, while a cryptic recent tweet sent to McGregor from Manny Pacquiao fuelled speculation the pair could meet in the ring next year.

Whatever the causes of McGregor's recent controversies and whatever he chooses to do next, one thing is clear: His 'Notorious' moniker is becoming increasingly appropriate. Unfortunately for the Irishman, that's becoming increasingly due to his actions outside the Octagon, rather than in it.